Perceptual errors are reported to cause an estimated 80% of all highway accidents (Treat et al, 1977). Inattention is reported to be the leading cause of collisions (Wang et al, 1996), and late detection of traffic conflicts is a basic driver error (Rumar, 1990). There is an enormous cost to society from accidents and errors attributed to the influence of alcohol, illegal and prescription drugs, medical conditions, or other disabling infirmity during the operation of equipment such as vehicles, trains, aircraft, ships, nuclear reactors, chemical processes, etc.
The International Council on Alcohol, Drugs, and Traffic Safety (ICADTS) provides overviews of the problems associated with alcohol, illegal drugs, and driving, especially in the following references:
(1) ICADTS Working Group on Alcohol Ignition Interlocks: Alcohol Ignition Interlock Devices I: Position Paper (2001), ISBN: 90-802908-4-x (reference is made especially to page 11, last paragraph to page 12, last paragraph);
(2) ICADTS Working Group on Illegal Drugs and Driving: Working Group Report: Illegal Drugs and Driving (2000), ISBN: 90-802908-2-3;
(3) ICADTS Working Group on Prescribing and Dispensing Guidelines for Medicinal Drugs affecting Driving Performance: Prescribing and Dispensing Guidelines for Medicinal Drugs Affecting Driving Performance (2001), ISBN 90-802908-3-1.
Especially regarding the influence of drugs and alcohol on perception and eye movements, reference is made to:
(4) Page, T. E. (1998): The Drug Recognition Expert (DRE) Response to the Drug Impaired Driver: An Overview of the DRE Program, Officer, and Procedures. Los Angeles Police Department (http://www.ci.la.ca.us/LAPD/traffic/dre/drgdrvr.htm);
(5) Leigh, R. J. and Zee, D. S.: The Neurology of Eye Movements, third edition, Oxford University Press (1999);
(6) Adler, E. V. and Burns, M. (1994) Drug Recognition Expert (DRE) Validation Study. Final report to Governor's office of Highway Safety, State of Arizona;
(7) Bigelow, G. E., et al., (1984) Identifying Types of Drug Intoxication: Laboratory Evaluation of a Subject Examination Procedure. NHTSA, DOT HS 806 753 (1985).
References (4) and (5) as well as other research show that numerous drugs—here the meaning of drug includes alcohol, prescription drugs and illegal drugs—including Central Nervous System Depressants, Inhalants, and Phenocyclidine (PCP) affect perception and eye movements. Effects on eye movement include horizontal and vertical gaze nystagmus (an involuntary but visible jerking of the eyeballs while gazing at an object), vergence deterioration, changes in pupil size, and blank staring (see references (4) and (5)). Interestingly, a test for horizontal gaze nystagmus was shown to be the best indicator of alcohol use (reference (4)). In reference (5), pages 561-564, numerous effects on eye movement by drugs are listed and references for these findings are provided. Other effects include difficulty remembering and following instructions, reduced ability to divide attention, sensory-motor coordination deterioration, and/or changes in pupil size. (Some of these difficulties, especially sensory-motor coordination and reaction time, have been exploited by similar ignition interlock patents.) Various types of nystagmus can be caused by various medical conditions.
In reference (4), an overview of the Drug Recognition Expert (DRE) program and the Drug Evaluation and Classification Program (DECP) is provided. The DRE program was started by the Los Angeles Police Department (LAPD) and developed in a body of research (e.g. references (6) and (7)). The original need for the DRE method was driven partially because the blood alcohol content (BAC) breath test results can be below the statutory level, yet the person can appear to be inexplicably impaired by drugs. The DRE uses a drug categorization system with seven categories with numerous drugs per category. The overall effects within each category are the same. The categories are: 1. Central Nervous System Depressants, 2. Inhalants, 3. Phencyclidine (PCP), 4. Cannabis, 5. Central Nervous System Stimulants, 6. Hallucinogens, 7. Narcotic Analgesics. An additional category, “Poly-drug Use,” is used when multiple drugs are used.
In addition to drugs, eye movement and perception can be influenced by a number of medical conditions or crises such as stroke, epilepsy, multiple sclerosis, uncontrolled diabetes, etc. and other operator states. Regarding such influences, it has to be considered that they produce effects that are similar to drug impairment (reference (4)). Reference is made to US Patent Application Publication 2001/0028309A1, paragraphs 79-82, disclosing a number of such examples for medical, psychological, and activity situations.
Furthermore, reference is made to the following documents: U.S. Pat. No. 3,780,311; U.S. Pat. No. 4,901,058; U.S. Pat. No. 4,912,458; U.S. Pat. No. 3,665,447; WO 87/07724; U.S. 2003/0037064A1; U.S. Pat. No. 4,983,125; U.S. Pat. No. 3,755,776; U.S. Pat. No. 3,886,540; U.S. Pat. No. 6,229,908 and U.S. Pat. No. 3,735,381.
In general, most of these documents refer to ignition interlock or similar devices that require the driver of a vehicle to execute some type of test before he can start the vehicle. However, it is considered detrimental that the driver actively has to execute such tests. Furthermore, the disclosed impairment measurements have several other disadvantages.